Problem to change tcp port in server.xml

I've installed today JIRA on a linux server with the tcp port 8080. It works well (i can access with http://@IP:8080 on a browser.

I want to change the tcp port to 80. I've changed the server.xml file ( <Connector port="80"), stop and restart jira with the user root (with the scripts stop-jira.sh and start-jira.sh) but when i tried to connect with http://@IP:80; i have an error on the page.